Submarine mine control system



May l, 1962 A. F. ENGLEHART ETAL 3,031,962

SUBMARINE MINE CONTROL SYSTEM Filed May 24, 1959 May 1, 1962 A. F. ENGLEHART ETAL 3,031,962

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SUBMARINE MINE CONTROL SYSTEM 9 Sheets-Sheet 9 Filed May 24, 1939 mNN United States Patent C) War Filed May 24, 1939, Ser. No. 275,426 28 Claims. (Cl. 102-11) (Granted under Title 3S, U.S. Code (1952), sec. 266) This invention relates to a system of submarine mine control, in which a group of mines submerged offshore and constituting a distant station is connected through a single conductor to a casemate or shore station, the respective mines of the group being remotely controlled from the casemate through the instrumentality of a normally inactive automatic selector situated at the distant station, whereby to permit the mines to be iired selectively from the casemate or automatically by impact. i

One of the objects of this invention is to provide a submarine mine control system wherein the components of a mine field submerged offshore may be fired by impact through the action of a normally dormant automatic selector mechanism situated in the midst of the mine field at the distant station and :functioning when a mine has been struck and armed by the impact to establish a path for the passage of electrical energy through the detonating elements of the mine from a source of high potential energy located at the casemate or shore station.

Another object of this invention is to provide a system of the type specified whereby the components of a submerged mine eld may `be'selectively red from the casemate or shore station through the conjoint action of an automatic selector situated at the distant station in the midst of the mine field and a series of interacting electromechanical devices controlled from the casemate and functioning when energized to cause the automatic selector to step to and lock on a selected mine for the purpose of establishing an electrical path for the passage of tiring current through the detonating elements of the mine from 4a source of high potential energy at the casemate.

Another object of this invention is to provide a system of submarine mine'control including a p-air of automatic selectors, one of the selectors being located at the casemate or shore station, the other being disposed at the distant station in the midst of the submerged mine field, the two selectors, which are normally at rest on the home position, being adapted to step in coordinated sequence to, and to stop on a mine circuit which has been armed or grounded, the operating circuits for the respective automatic selectors embodying means for restoring the proper sequence to the selectors should their order of stepping relation be disrupted.

Another object of this invention is to provide -a system of submarine mine control including a group of mines submerged offshore, an automatic selector situated in the midstvof the'mine group'and coacting therewith to distribute electrical energy to the components of the group, a selector located at the casemate and adapted to step in coordinated relation with the offshore selector whereby the operator at the casemate or shore station may be informed at any time which mine in the group is operatively` connected to the mine control assembly.

Another object of this invention is to provide a system of submarine mine control which when rendered alert by application of the operating power will be mechanically and electrically silent, that is to say, its operation will not involve the production of disturbances of either a mechanical or electrical nature which could be detected by detecting apparatus employed for the purpose of locating the mine eld.

Mice

Another object of this invention is to provide a submarine mine control system embodying electro-mechani cally controlled units which normally disrupt the tiring circuit and preclude the application of firing power to the shore cable until the selector at the distant station has definitely locked on the mine selected for tiring.

Another object of this invention is to provide a mine 4control system including interacting electro-mechanical means automatically controlled for removing all power from the shore cable and maintaining the system in this condition until the high potential energy circuits have been broken and the electro-mechanical components of the system restored to their normal positions, whereby to preclude accidental firing of the mine.

Other objects of this invention are to provide a submarine mine system wherein one or more mine groups may be controlled or supervised from a single supervisory assembly located at the casemate or shore station; to enable the electrical characteristics of the entire system and of any mine circuit in the system to be readily ascertained at the shore station; to furnish a system which permits the nineteen mines of the submerged mine group to be successively red while restricting application of thevhigh potential tiring power to each mine in the order in which the respective mines have been conditioned for tiring and to afford a control system which utilizes an electronic discharge device to prevent the back iiow of high voltage currents through the system to the generating plant.

With these and other objects in view this invention consists of certain details of construction, combination and arrangement of parts to be more particularly hereinafter described and claimed.

Briey stated, this invention comprises a shore station or casemate consisting of a power unit (not shown) adapted to supply electrical energy for the system; a mine control assembly functioning to determine the flow of energy to the shore cable; a supervising assembly adapted to be connected with one or more mine control assemblies to enable supervision of the system and a distant station including a submerged mine field of nineteen mines and a distribution box situated in the midst of the mine field, the distribution box containing an automatic selector connected through the distribution box with the shore cable and with each of the nineteen mines, the selector functioning to establish an electrical path through each mine whereby it may be fired on impact or selectively fired from the casemate or shore station and for other purposes.

Referring more particularly to the accompanying drawings in which coresponding parts are indicated by similar reference characters:

FIG. l is a diagrammatic view partially in section and in elevation of casemate assembly A, a fragment of the connections extending between the source of electrical supply and the assembly, a portion ofthe connections between assembly A and assembly B and a part of the connection between assembly A and the distant station, and illustrating the components of assembly A in their normal positions;

FIG. 2 is a diagrammatic view partially in section and in elevation of casemate assembly B, a portion of the electrical connection extending between assembly A and assembly B, a fragment of the connections between the source of electrical supply and assembly B and a part of the shore cable between assembly A and the distant station and illustrating the components of assembly B in their normal position, with the wipers of the casemate selector serving its four levels on their home positions;

FIG. 3 is a fragmentary diagrammatic view partially in section and in elevation of distant station assembly C, a portion of the shore cable extending from assembly A,

fand illustrating the components of assembly C in their normal position with the two wipers of the distant station selector on their home positions and the notch in the disk of said distant station selector overlying the remaining home position and showing in dotted outline the first step of the wipers after they have left their home positions;

FIG. 4 is a fragmentized diagrammatic View of the system partially in section and in elevation and illustrating in full lines the paths taken by the 110 volt operating current kfrom its distributing terminal to the grounds at the casemate and at the distant station during the stepping operation of the casemate and distant station selectors and which are established immediately after the selectors have left their home positions, and said view showing in dotted outline those components of the system which are in vtheir normal positions and which aid in forming certain of the paths for the 110 volt operating current to ground and further showing in full lines and in section,

kcertain elements of the system which are in their operated positions and through which the current passes to ground;

FIG. 5 is a fragmentized diagrammatic view partially in section and in elevation of a fragment of the vshore cable, the distributing assembly C at the distant station including the locking relay unit, the timing relay unit, the motor magnet, the distant station selector and a portion of the mine assembly E, and illustrating in full line the path of operating current from the shore cable to ground when the operating switch has been closed and the system is on the alert and showing in dotted outline the path taken by the 110 volt operating current immediately after a mine has been lstruck and the impact mechanism operated to move its ball to the position shown in dotted outline, certain of the components of the system through which the operating current flows and which are Yin their normal position being shown in dotted outline and certain elements through which the current passes but which are in operated position, being disclosed in full lines and in section;

FIG. 6 is a fragmentized diagrammatic view partially in elevation and in section and illustrating in full lines the path to ground taken by the 1l() volt operating current and the 600 volt tiring current when the distant station selector has locked on a grounded mine, certain of those components of the system which are in their normal positions, but through which the circuit passes, being shown in dotted outline and certain elements through which the current passes but which are in their operated position, being shown in full lines and in section;

FIG. 7 is a fragmentized diagrammatic view partially in section, partially in elevation, of the paths taken by the ll() volt operating circuit from its distributing terminal to ground when the coordinated stepping relation of the casemate and distant station selectors has been disrupted, the paths to ground taken by the operating current from its distributing terminal being shown in full line; the components of the system through which the eurent passes and which are in their normal positions, being shown in dotted outline, and those components through which the current passes but which are in operated position, being shown in full line and in section;

FIG. 8 is a fragmentized diagrammatic view partially in section and in elevation of the paths taken by the `l1() volt operating current to ground when the distant stations selector has stopped on a grounded mine, said paths to ground being shown in full lines; the components of the system which are in their normal position but through which the current passes being shown in dotted outline and those through which the current passes, but which are in operated position, being shown in full lines and in section;

FIG. 9 is a side elevation of the distant station selector;

FIG. 10 is a top plan view of the distant station selector;

1l is a fragmentized top plan view of the housing for the distributing assembly at the distant station, with cover removed;

FIG. l2 is a transverse vertical section taken on the line 12-12 of FIG. l1;

FIG. 13 is a side elevation of Ithe cover for the housing, shown in FIGURES 11 and l2, the fastening element for the cover being shown in position, and

FIG. 14 is a fragmentary detail of the distant station selector showing the relation of the wiper arms and notch in the selector disk.

The mine control systems heretofore designed have involved certain Yserious defects due to the use of -alternating current as operating power for the system, a continuously rotating selector at the distant station, or circuit arrangements at lthe distant selector which under certain conditions rendered it possible for the high voltage tiring current to reach the mine. The present invention overcomes these and other defects by using direct instead of alternating current as the power for operating the systern, by substituting a normally inactive selector in place of a selector of the continuously rotating type and by isolating the re mine circuit from the remaining mines. With these and other important provisions there is effected a system which to a large extent is detection proof and which affords a vmaximum degree of safety against premature mine explosions.

In the illustrated embodiment characterizing this invention and with special reference to FIGS. 1 and 2 of the drawings, there are shown mine control and supervisory assemblies A and B respectively, which in connection with the power unit, not shown, constitute the casernate or shore station. This station is adapted to be connected by a single conductor Y with the distant station, shown on FIG. 3, which consists of a distributing box assembly C and a mine field D. These three views when placed in end to end relation and collectively considered disclose the complete system which for the purpose of this discussion will hereinafter be considered under the headings andin the order to wit:

Casemate-Power Supply;

Casemate-Mine Control Assembly; Casemate-Supervisory Assembly;

Distant Station-Distribution Box Assembly; Distant Station-Mine Field;

Circuits and Their Function;

Conclusion.

CASEMATE-POWER SUPPLY The requisite electrical energy for the system is furnished by a casemate power unit, not shown, having facilities for generating volts direct current adapted to serve as operating power for the system, 45 volts alternating current for the signals in the supervisory assembly, 250 volts direct current for clearing the mines and locking the distant station selector lon a selected mine, 110 volts alternating current adapted to heat the filament of the two-element electronic device in the mine control assembly and for operating certain audible and visible signals in the mine control and supervisory assemblies, and 600 volts rectified current for tiring the mines. This power is rendered available at the distributing terminals of the casemate mine control and supervisory assemblies, as will hereinafter appear.

CASEMATE-MINE CONTROL ASSEMBLY The 110 volt direct current, the 600 volt rectified current and the 110 volt alternating current referred to in the preceding paragraph, are conducted to terminals 1, 4, 5 and 6 of the group of terminals numbered 1 to 6 inclusive, attached to the back of the casemate panel; this power being applied to the system as follows: 110 volts direct current terminal ll, 600 volts rectified current terminal 4, 110 volts alternating current terminals 5 and 6. The remaining terminals 2 and 3 of the group are adapted to be connected to the outgoing leads of signal circuits, which hereinafter will be referred to.

Mounted on the casemate panel is the mine control assembly A which for the purpose of 'this discussion will be broken down into the subordinate groups and units to wit: electronic valve group; signal group; power control group and relay group which includes the pilot relay unit; the control relay unit; the guard relay unit and the firing power relay unit.

The components of these groups and units, their electrical connections and their purpose will now be described. The electronic valve unit consists of a transformer 7 having primary and secondary windings 8 and 9, the primary winding`8 being connected with the ll() volt alternating current supply terminals 5 and 6, via conductors 10 and 11, and the secondary winding 9 being connected to the input and output leads 12 and 13 of the ilament 15 of the two-element electronic valve 14, the plate 16 ,of which is connected to one end of conductor .17. This valve or diode 14 is included in the circuit of the operating power so as to prevent the back-flow of high potential energy to the power operating unit which would be possible should the switch of the control relay unit fail to release when tiring power is llowing through the system.

The signal group is composed of four signal lamps, colored green, red, white and red and numbered respectively 18, 23, 28 and 38. The green signal 18 has its terminal 19 connected via conductor 21 to ground 21 and the remaining terminal 20 connected to one end of conductor 22. The red signal 23 has its terminal 24 connected to one end of conductor 26 branching from conductor 97, and the remaining terminal 25 connected to ground 25 via conductor 27. White signal Z8 has `its terminal .29 connected to the upper end of conductor 31 and the remaining terminal 30 connected to one end of conductor 32. Red signal 38 has its terminal 40 connected to one end of conductor 41 and the remaining terminal 39 connected to outlet terminal 2, via conductor 42. The white signal 28 when illuminated, indicates 'that the distant station selector is on the home position; the red signal that the distant station selector has locked on `a mine circuit and that the system is in condition for the application of ring power. This signal also serves to indicate that the distant station selector' has stopped on a grounded mine circuit and that the system is ready for the `application of clearing power. The green and white signals glowing simultaneously indicate that a mine has been red and that the distributing box fuse in the circuit of the tired mine has been blown. These two signals also indicate that all power has been removed from the shore cable and if clearing instead of tiring power has been applied to the system, they likewise show that the fuse in the circuit of the red mine has been blown. The red signal 38 serves to inform the easemate operator that the tiring powera switch at the power unit `(not shown) has been closed and in consequence tiring power is available at the Vcasemate panel for the assembly A.

The power control group is composed of an operating switch 33, a tiring switch 43, the two switches controlling respectively the application of operating and iii-ing power to the system. A start key switch unit 56 provides a secondary control of the ow of operating power through the system and a clearing key switch unit 60 determines the tiow of clearing power to the distant station. Operating switch 33 includes movable switch blades 33a and stationary contacts 34a, 34b, 34C and 34d, of which contact 34a is connected to the 110 volt direct current terminall via conductors 45 and 74, contact 34b to the free end of conductor 32, extending from the white signal, contact 34e to the free end of conductor 17, extending from the plate 16 of the electronic valve 14, and contact 34d to ground 36 via conductor 35. When switch 33 is in closed position the plate circuit of the diode 14 6 is connected with the ll() volt direct current source of supply and one side of the white signal 28 is grounded.

The firing switch 43 includes movable switch blades 43a and the stationary contacts 44a, 44b, 44e, 44d, 44e and 44]", of which contact 44a is connected to one end of conductor 49 extending from conductor 50; contact 44h to distributing terminal 4 (the connection being made via conductor 51, to which the l600 volt rectified current is applied); contact 440 to outlet terminal 3 via conductor 52; contact 44d to one end of conductor '53 extending from the mid-point of secondary winding '9 of transformer 7; contact 44e to one end of the conductor 54 and contact 44]c of distributing terminal 6, via conductorsSS and 11. When firing switch 43 is in closed position, 600 volts rectitied current, constituting the iring power, is applied to the system, likewise a circuit through a green signal at the power unit (not shown) is completed to inform the operator at the power unit that firing power has been applied to the mine control assembly A. The switch 43 also closes a circuit to ground through one of the windings of the control relay unit, as will hereinafter appear.

Start key switch unit 56 comprises a pivotally mounted start key 56a and a switch set 56b including resilient fingerlike contacts 1a and 2a of which contact 1a is adapted to be engaged bythe tip ofthe key to separate said contacts when the key is operated in the direction of the arrow, thus disrupting the operating power circuit. Contact 1a of switch set 56h is connected to the free end of conductor 57 branching from conductor 53, while the remaining contact 2a is connected to conductor 59 via conductor 58.

The clearing key switch unit 60 includes a pivotally mounted clearing key 60a and a switch set 60b embodying stationary finger-like contacts 1b, 3b, 5b and movable interconnected contacts 2b-4b, adapted to be engaged by the clearing key 60a, so that when said key is actuated in the direction of the arrow the normally engaged contacts 4b-'5b will be separated and the normally separated contacts lb-Zb and Sab-4b will be brought into engagement. Contact 1b of switch set 60b is connected to conductor 50 lvia conductor 63. Contact 2b to conductor 57 via conductor 64, contact 3b to one end of conductor 65, contact 4b to one end of conductor -66 and contact 5b to the free end of conductor 54, extending from contact 44e of the firing switch.

Clearing switch unit 60 when in its operated position functions =to close the volt operating circuit through one of the windings of the control relay unit, to complete the 250 volt clearing circuit through the distant station selector and to open the tiring circuit.

Aspreviously stated the relay group (FIG. l) consists of the pilot, control, guard and firing power relay units. These will now be considered in the order of their enumeration. Pilot relay unit 67 embodies a winding 68, armature 69, and switch operating arm 70, which is interlinked with and controlled by the armature 69 to operate switch set 71 composed of a stack of contact members numbered 1c to 5c inclusive.

In this connection, it is to be understood the interlinked construction between the .armature 69 and arm 70 is merely a diagrammatic showing to indicate control of the arm by the armature, since in actual practice this relay unit is of the telephone type as shown in the patent to Michael Setter, number 1,317,597, patented September 30, 1919, wherein aV stack of contact members are mounted on the relay and operated by an armature-controlled mechanism as will be understood without further discusslon.

When winding 68 of relay unit 67 is energized switch set 71 will be moved to operated position from the released position shown in the drawings. In other words the interconnected movable contact members 2c and 4c ofthe stack will be moved relative to the stationary members to separate contacts 1c and 2c and to close the normally separated members 2c-3c and 4c-5c.

To include contact members 1c to 5c of the stack in the vinstant system, Contact member 1c is connected via conductor 73 to conductor 31; contactmember 2c to the 110 volt direct current 'distributing terminal 1 via conductor 74; contact member 3c to one end of conductor 75; contact member 4c to the 110 volt alternating current distributing terminal 6 via conductors 76 and 11, said conductor 76 being connected intermediate its ends to the branch conductor 41 extending from terminal 40 of red signal 38; contact 5c is connected to one end of conductor 77.

To include winding 63 of relay unit 67 in the system, one extremity of said winding is connected to conductor 84 and the other to conductor S3, for a purpose which will hereinafter appear. Pilot relay unit 67 when permanently energized operates the switch set 71 to disrupt the circuit of white signal 2S, close that of red signal 23, open the circuit of the guard relay unit, close that of the tiring power relay unit, complete the circuit of an alarm bell and a red signal in the supervising assembly B, hereinafter to be mentioned.

The control relay unit 78 comprises two winds la-Zb, armature 79 and arm 80 which is interlinked with and controlled by the armature to operate switch set S1 as in the case of the pilot relay unit hereinbefore described. Switch set 81 is composed of a 'stack of contact members 1d to 6d inclusive, having contacts 2d-3d-5d interconnected for simultaneous movement by the armature controlled 'arm 80 so that energization of the windings Irl-2b of the relay unit moves the switch set from the released position, shown in the drawings (FIG. 1), to operated position which separates contacts ld-Zd and engages contacts Sad-4d and Srl-6d.

To tie the switch set 81 to the instant system contact member 1dy is connected via conductor 83 to conductor 33; contact member 2d to the free end of conductor 50; contact member 3d to the free end of conductor 59; contact member 4d to Ithe free end of conductor 22; contact member a' to the free end of conductor 76 via conductor 85 'and contact member 6d to conductor 77 via conductor 86.

To include the relay unit 78 in the system, winding 2b has one extremity connected to conductor 22 via conductor 82 and the other end connected to ground 8S through conductor 89 and balancing resistance 90, while the remaining winding 1a of the relay unit 78 has one extremity connected to conductor 91 and the other extremity to the free end of conductor 83, as clearly shown in FIG. l of the drawings.

The control relay unit 78 when operative functions to close the circuit through the green signal 18, remove all power from the short cable Y, complete the circuits of an audible and visible signal in the supervisory assembly B and disrupt the normal path of the 110 volt direct current through the pilot relay unit.

Guard relay unit 92 consists of winding 93, armature 94 and arm 95 which is interlinked with and controlled by the armature as in the case of the other relays previously described. As the guard relay 92 must be slow to release, its armature 94 is counterweighted as at 94a. Arm 95 is adapted to operate the switch set 95a consisting of the two contacts 1e-2e which are separated when the relay unit energizes.

To include the switch set 95a in the system contact 1e is connected to the free end of conductor 75 and contact 2e to one end of conductor 97. To include the winding 93 of the relay unit 92 in the system one end of said winding is connected through resistance 95b to conductor 31 while the other end of said winding is connected to ground 96 via conductor 96a. When in its operated position guard relay unit 93 serves to interrupt the circuit through the tiring power relay unit 93 hereinafter to be mentioned.

The firing power relay unit 98 consists of winding 99, armature 100, armature arm 101, which is interconnected with and controlled by the armature to operate switch set 102 composed lof the stack of contact members 1f to 4f inclusive, having contact members 1f-3f interconnected and adapted to be simultaneously moved by the armature arm 101to engage contact members 1f-2f and 3f-4f. To associate the switch set 102 with the instant system, contact 1f is connected to the free end of conductor 91; contacts 2f and 3f are interconnected and contact 4f is connected to the free end of conductor 66. To connect the winding 99 of the relay unit 9S to the system, said winding has one end connected through resistance 103 to the lower end of conductor 97, and the other end to ground 104 -via conductor 105, as clearly shown in FIG. l of the drawings. When in its operated position, relay unit 98 serves to complete the 600 volt tiring power circuit and likewise the 250 volt clearing power circuit to the shore cable Y for a purpose hereinafter to be described.

In order to interconnect the mine control assembly A with the supervisory assembly B hereinafter to be referred to, the four leads 50, 59, 65 and 77, extending from the mine control assembly are connected to the terminals 50a, 59a, 65a and 77a of terminal block 106 (FIG. l) and these terminals are in turn connected Via conductors 50b, 59h, 65h and 77b to the distributing terminals 50c, 59C, 65C and 77c on the supervisory panel upon which there is mounted the supervising assembly B (FIG. 2) which will now be described.

Casemate 0i* Shore Station Supervisory Assembly B To furnish the supervising assembly B with the requisite power it is equipped with power terminals 110, 111, 112, 113 and 114, which are connected to the casemate power unit (not shown) and supplied with power as follows: terminal 110, 250 volts direct current; terminal 111, volts direct current; terminals 112 and 113, 45 volts alternating current and terminal 114, 110 volts alternating current.

For the purpose of adequately supervising one or more mine control assemblies and their respective mine groups, there is provided a supervising assembly B, having the components to wit: alarm unit, jack group, start key controlled switch set, metering unit, test key controlled switch set, mine key group, mine signal group, relay group and automatic selector, which are conveniently arranged on a suitably dimensioned supervising panel at the casemate or shore station, as clearly shown in FIG. 2 of the drawings. These components, their electrical connections and functions will now be described in detail and in the order of their enumerations.

The alarm unit designated H, consists of a bell 115, a red signal 116, and a switch 117 and is included inthe system as follows: terminal 118 of the bell is connected via conductors 119 and 120 to distributing terminal 77c and its other terminal 121 is connected to terminal 122 of the switch 117, the remaining terminal 123 of which is connected via conductors (124) and 125 to power terminal 114. The red signal 116 has one of its terminals connected to alarm terminal 77c, via conductor 120 and the other terminal to power terminal 114. Assuming switch 117 to be closed the bell 115 will be sounded and the red signal illuminated when the pilot relay unit and the control relay unit are separately or collectively operated. Opening the switch 117 disrupts the bell circuit. The red signal however, will continue to glow until the pilot relay unit or the control relay unit has been released.

The jack group includes a center jack I and a group jack I. Center jack embodies a series of stationary and movable contact members 1g to 8g inclusive, the movable Contact members 1g-3g-4g-5g and 8g being shiftable relative to the remaining stationary contact members when a dummy plug 126 is inserted in the jack, as will be understood without further discussion. In the instant assembly but two of the contact members of the center jack are used, namely '7g and 8g and these are included in the system as follows: contact 7g is connected to one end of conductor 127 and contact 8g to the 45 volt ter- 9 minal 113 via conductor 128. Center jack I functions as a seat for the dummy plug 126 and also serves to disrupt the 45 volt circuit of the mine signaling group.

Group jack J embodies a set of stationary and movable contact members designated 8h-7h-1h-2h-3h-4h-5h and 6h. Normally these contact members are disposed, as shown in FIG. 2 of the drawings, but when dummy plug 126 is removed from the center jack and inserted in the group jack the contact members Slt-7h, 1h-3h and h-6h will be separated and the contact members lh-Zh and lh-6h brought into engagement for a purpose hereinafter to appear. To tie the group jack 1 to the instant system contact 8h is connected to terminal 59C via conductors 129, 130 and 131; contact member 7h to the 110 volt direct current terminal 111 via conductor 132; contact member 1h to the distributing terminal 59C via conductors 131', 130 and 131, contact member 2h to one end of conductor 133, the other end of said conductor being connected with conductor 134; contact member 3h to terminal 50c via conductor 135, resistance 136 and conductor 140; contact member 4h to one end of conductor 137; contact member 5h to terminal 59C via conductor 138', resistance 139, conductor 138 and conductor 131; contact member 6h to terminal 50c via conductors 139 and 140. The group jack I through certain of its contact members serves to normally establish a path for the operating current between the terminals 59C and 50c so as to permit the system to function without regard to the use of the supervisory assembly. When the dummy plug 126 is inserted in the group jack however, the movable contact members are shifted relative to the stationary members to interconnect the various components of the supervisory assembly with the mine control assembly, as will hereinafter appear.

The check key controlled switch set designated K is composed of a pivotally mounted key 142a movable to the right and left, as indicated by the arrows, to operate switch set 14Zb embodying movable and stationary contact members 1i to 9i inclusive, of which contact members 4i-7i-9i are interconnected for simultaneous movement. When key 142e is moved to the left contacts 4i-7-9i will be actuated to separate the normally engaged contacts 3-4i-6i-7z'-8-9i and to engage the normally separated contacts 411-51'. When the check key is moved to the right the normally engaged contacts 1i-2i will be separated, as clearly shown in the drawings. To include the check key controlled switch K in the system contact member 1i is connected to conductor 137, via conductor 134, capacity 146' and resistance 147'; contact member 2i to one end of conductor 143; contact member 3i to one end of conductor 143'; contact member 4i to the free end of conductor 127; contact member 5i to one end of conductor 144; contact member 6i to one end of conductor 145; contact member 7i to one end of conductor 146; contact member 8i to one end of conductor 147; contact member 9i to one end of conductor 148. Check key controlled switch set K coacting with the automatic casemate selector to be hereinafter referred to, controls the 45 volt power circuits to the mine signal lights for signaling and checking purposes.

To inform the operator `at the casemate with respect to the electrical status of the system, there is provided a metering unit composed of a miiliammeter key L, a milliammeter MA and a volt meter V. Milliammeter key L consists of a series of contact members 1j to 8]' inclusive, two of said members 3]'-61 being interconnected to provide a shifta'ble element or key operable to the left or right to the positions designated clear and operated respectively on the drawings. To connect the metering unit to the instant system the contact members of the milliammeter key are connected as follows: contact member 1]' to the 250 volt direct current terminal 110 via conductor 150; contact member 2]' to conductor 151 via conductor 152; contact member 3]' to the positive binding post 153 of milliammeter MA via conductor 154; contact l@ member 4j to one end of conductor 155; contact member 5j to one end of conductor 151; contact member 6]' to one end of conductor 156; contact member 7]' to conductor via conductor 157, and contact member 8]' to the free end of conductor 137. The remaining binding post 158 of the milliammeter MA is connected to conductor 156' via conductor 159. Voltmeter V has its positive binding post 160 connected to the conductor 154 via conductor 161 and the remaining binding post 1-61' connected to ground 162 via conductor 163. With the milliammeter unit connected as stated when the switch key element 149 is moved to the left to the position designated clear, the milliammeter MA and Voltmeter V will be included in the 250 volt direct current circuit employed for clearing purposes. Shifting the milliammeter key L to the right into the position designated operated includes the milliammeter and Voltmeter in the ll() volt direct current operating circuit of the system, as will be understand lwithout further discussion.

To enable adjustment of the bailast resistance until the total resistance of the shore cable is 200 ohms at which point the milliammeter MA should give a reading of 67 milliammeters,` there is provided a test key controlled switch set designated M consisting of a pivotally mounted while movement of the key to the left opens the normallyy closed contacts 5k-6k and ik-8k, as clearly shown in the drawings.

When test key 150a has been moved to the right the 250 volt terminal, designated 110, will be connected with the test contact T on the casemate automatic selector and the circuit to ground 199 will be opened. Movement of the test key to the left disrupts the 250 volt circuit to the terminal 65C and opens the milliammeter shunt circuit.v To include the test key controlled switch set in the instant system contact member' 1k is connected to one end of conductor 165; contact member 2k to one end of conductor 166, the opposite end of said conductor being connected to conductor 167; contact member 3k is con- M'z'ne Key Group To apply locking power to a predetermined mine at the distant station, there is provided a mine key group composed of nineteen mine keys, one for each mine at the distant station and these keys are designated mkl to mk19 inclusive. In the drawing but two of these keys mk1 and mk19 are shown, as this showing is deemed sucient-or the purpose of the instant disclosure.A Each mine key includes four contact members designated 1m,

2m--3m-4m. The contact members 2in-3m of each key are interconnected and adapted to be simultaneously moved relative to the remaining contact members of the set to break a normally established ground circuit to ground 199 or to close the 250 volt circuit to the corresponding contact of the automatic selector, as will hereinafter appear. The mine keys shown are connected with the system as follows: contact mem-ber 1m of mine key mkl is connected to one end of conductor 172a', contact member 2m to conductor 150 via conductor 167, resistance 167a and conductor 1617; contact member 3m with one end of conductor 173 branching from conductor 196; contact member 4m with one end of conductor 174.

The contact members of mine key mk19 are connected as follows: contact member 1m to one end of conductor 172b; contact member 2m to conductor 166, common toV all the keys; contact member 3m to the free end of conductor 174, likewise common to all the keys; and contact member 4m to the free end of conductor 169. With the nineteen keys connected to the system in the manner stated, depression of a mine key establishes a 250 volt locking circuit through the correspondingly nurnberedV mine at the distant station, as will hereinafter appear.

To inform the casemate operator with respect to the particular mine at the distant station upon which the system has locked, there is provided a group of suitably colored signal lights numbered msl to ms19 respectively, the circuits of which are controlled by the casemate selector stepping in coordinated sequence with the distant station selector. In the present instance but two of these lights, m51 and ms19 are shown in connection with a white signal light ms20 which indicates the home position of the respective selectors.

The signal lights shown are connected to the system as follows: one terminal of each of the signal lights msl and ms19 is connected to a common conductor 175 branching from conductor 147. The remaining terminals of each of the lights are connected to conductors 176@ and 17711 extending from the contacts c1 and C19 of the casemate selector CS, hereinafter to be described. One terminal of the white light ms20 is connected to conductor 179 extending from terminal 9i of check key K. Conductor 179 is connected through branch conductor 179 with the 45 volt alternating current terminal 112. The remaining terminal of this light is connected via conductors 191 and 223 to the home contacts H3 and H4 of the automatic selector at the casemate, to be hereinafter referredto. With this arrangement it will be apparent as the casemate selector steps from contact c1 to C19 the nineteen signal lights will be successively illuminated and when the selector comes to rest on the home positions H3 and H4 the circuit throughthe white light ms20 will be completed.

Relay Group As previously stated, the relay group consists of an impulsing relay unit P and a synchronizing relay unit Q. The impulsing relay unit P is composed of windings c and d, armature 181 and arm 182, which is interlinked with the armature and adapted to operate switch set 189. This set consists of a stack or" contact members 1n to 6u inclusive. The arm 182 coacts with the interconnected contact members 2n and 411 to move these members relative to the complemental members whereupon when winding d of the impulsing relay unit is energized, the switch set will be moved to operated position which opens the normally closed contacts liz-2n and S11-611 and closes the normally open contacts 2n-311-4n6n, for a purpose to hereinafter appear.

. To include the switch set 180 in the instant system, contact member 1n is connected to one end of conductor 183; contact member 2n is connected to one end of conductor 184; contact member 311 is connected to one end of conductor 145 via conductor 185 and resistance 186; contact member in is connected to conductor 143 via conductor 187; contact member Sn to one end of conductor 188; contact member 6u to the upper end of winding d, the free end of said winding being connected to one end of conductor 189. The remaining winding c of relay unit P has one terminal connected to conductor 143, and

its other terminal to conductor 145 through resistance 190.

VThe functions of the impulsing relay unit P are (a) to momentarily disrupt the operating circuit through the motor magnet of the casemate or supervisory selector during the period that the distant station selector is step ping in order to maintain the coordinated sequence in operation between casemate and distant station selectors; to hold the circuit through the casemate or supervisory selector in an open condition when a steady current of at least 50 milliamperes ows through the winding d of the impulsing unit. This condition will exist when the system has stopped on an armed mine (which normally draws 62Vmilliammeters), or on a mine circuit having a groundnumerically less than 500 ohms; to establish a circuit to ground through the winding c to send the casemate selector to its home position and restore the normal operating sequence to the casemate `and distant station selectors should they be out of step.

synchronizing relay unit Q is composed of winding 192, armature 193 and arm 194, which is interlinked with and `controlled by armature 193, to operate switch set 195 consisting of a stack of contact members 1o to 6o respectively, the three contact members 20-40-50 being interconnected for simultaneous movement by the arm 194 which moves the switch set to operated position when the winding 192 of the synchronizing unit has been energized. Movement of the switch set to operated position opens the normally closed contact members 10-20-30 and 4o and closes the normally open contacts 5o and 60.

The switch set 195 is connected to the system as follows: contact member 10 is connected to conductor 146, via conductor 196, capacity 196', resistance 197 and conductor 198; said conductor 196 being also connected to the free end of conductor 173, as clearly shown in the drawings (FIG. 2); Contact member 2o is connected to ground 199 via conductor 200; Contact member 30 is connected to the free end of conductor 147; contact member 40 to the free end of conductor 148; contact member 5o to the lower end of winding 192 of the synchronizing relay unit, the opposite end of said winding being connected to the free end of conductor 189; contact member 60 is connected to conductor 201. One end of conductor 261 is connected to the winding 192 adjacent its .lower end, the remaining endof said conductor is connected through capacity 202 and resistance 203 to the lower end of winding 192. Likewise the lower end of winding 192v is connected to the free end of conductor 155, for a purpose which will hereinafter appear.

The purpose of the synchronizing relay unit Q is to disrupt the synchronizing circuit to ground during normal stepping of the selectors or when the system has stopped on a contacted or selected mine to prevent return of the casemate selector to its home position. It is also the purpose of this unit to break the mine signaling circuit during the operation of rechecking, as will hereinafter appear.

CASEMATE-SUPERVISORY ASSEMBLY The automatic selector in assembly B is of the type shown and described in the treatise entitled Automatic Telephone Practice, 3d edition by Harry E. Hershey, this selector, which for the purpose of the instant discussion,

I will be referred to as the casemate or supervisory selector CS, is adapted to step in coordinated sequence with the distant station selector, and briefly stated, it comprises a contact bank in the form of a half cylinder which is served by four wipers having their wiping ends arranged apart so that when the wiping end of a wiper steps o the last contact in the row of contacts, the other wiping end of said wiper will engage the first contact in the row of contacts.

The contact bank is made up of four contact levels A-A, B-B, C-C and D-D, and designated respectively Locking Level, Synchronizing Level, Signal Level Direct, Signal Level Check. The wiper set of the selector is composed of wipers 204, 20S, 206 and 207, which are suitably mounted in insulated relation on a common shaft 207. Shaft 297 is adapted to be rotated in the direction of the arrows -by a step-by-step mechanism including a motor magnet MM, comprising winding 208, armature 2539 and armature arm 216, the latter being interconnected with the armature 299 and having a stepping pawl (not shown) adapted to coact with a ratchet ing lights ms1-ms19 inclusive. ductors are shown in the present instance, namely 176a 13 (not shown) mounted on shaft 207 so that the return movement of the arm 210 after its retraction, will impart a step-by-step rotary movement to the four wipers of the selector.

When winding 208 of motor magnet MM energizes, arm 210 will be retracted and when said winding 208 i s deenergized the arm will be restored to its original position under spring action. This retraction of the arm and subsequent return to its initial position functions to simultaneously advance the wipers 204, 205, 206 and 207 in a step-by-step fashion, as will be understood without further discussion. As the arm 210 retracts it separates the make-and-break contacts 211 and 212 and as said arm is restored by spring action to its normal position, as shown in FIG. 2 of the drawings, said contacts 211 and 212 are returned to their normally engaged relation.

To include the automatic selector in the system, the

upper end or" its motor magnet winding 208 is connected to one end of branch conductor 213 extending from conductor 143. The opposite end of winding 208 is connected to conductor 188. Make-and-break contact 211 on the motor magnet MM is connected to one end of conductor 214, the other end of said conductor being attached to a conductor 215, which through resistance 216 and capacity 217 is connected to the remaining makeand-break contact 212, likewise connected to the free end of conductor 184. t In regard to the contact lbank of the automatic selector, the level A-A and designated Locking Level is adapted to have its contacts a1-a19 connected to the free ends of the nineteen conductors adapted to extend from the nineteen mine keys mkl to mk19 inclusive. In the instant disclosure but two of these conductors are shown, namely 172a-172b extending from the mine keys mkl and mk19 and these are connected to the contacts on level A-A numbered a1-a19 respectively.` Level A-A is also provided with a testing contact T and a home contact H1, the testing `contact T being connected with the free end of conductor 165 extending from contact 1k of test key M, for a purpose hereinafter to appear.

The contact level B-B designated synchronizing Level has its contacts bl-b23 interconnected and attached to the free end of conductor 220 extending from conductor 168. One of the remaning contacts b24 1s connected to the free end of conductor 168 via conductor 221 and breaking resistance 222. The other of the remaining contacts b24 is adapted to function as the home position designated H2 for the wiper 205.

The contacts c1 to c19 of the level C-C designated Signal Level Direct are adapted to be connected to the nineteen conductors extending from the mine signal lights designated ms1-ms19. In the present instance but two of the contacts c1 and C19 are shown connected, contact c1 being connected to one side of light msl Via conductors 176b and 176a and contact C19 to one side of light ms19 via conductor 177n. The home contact H3 of level C-C is connected to the home contact H4 of level D-D via conductor 223. Conductor 223 is in turn connected to the free end of conductor 191 extending from one side of the signal light ms20 indicating the home position of the selector wipers. The remaining side of the signal lights ms1-ms19 is connected to conductor 175 branching from `conductor 147. 1 The remaining side of signal light ms20 is connected via conductor 179 with contact 9i of check switch K. V

Contacts d1 to d19 ofthe level D-D designated Signal Level Check are adapted to be connected to nineteen conductors extendingfrom one side of the mine signal- But two of these conand 177n, conductor 176e being connected to` contact d1 and conductor 177n to contact d19 via branch conductor 225. In this connection it is to be noted that contacts of level D-D advance numerically from d1 to d19 in an anti-clockwise direction, while in the signal level C-C the numbers of the contacts advance numerically in a clockwise direction. With this arrangement it is possible to use the mine signal lights for checking purposes, as will hereinafter appear.

In order to connect the wipers of tthe automatic selector to the instant system, wiper 204 is connected to the free end of conductor 143; wiper 205 to the free end of conductor 146; wiper 206 to the free end of conductor 143 and wiper 207 to the free end of conductor 144, as clearly shown in FIG. 2 of the drawings.

Having outlined the arrangement and electrical connections of the components of the casemate assembly B, attention will now be directed to the distant station.

DISTANT STATION The distant station includes a distributing box assembly C, and a mine tiel-d D, composed of nineteen mines, the respective mines and the distributing assembly C being in electrical relation with the mine control assembly over a single conductor or shore cable Y extending from the variable ballast resistance Z in assembly A to the distributing box assembly at the distant station, as clearly shown in FIG. 3 of the drawings.

Distributing box assembly C for the purpose of this description will be considered in the order of its principal groups and units to wit: distributing box or casing DB;A locking relay unit LR; timing relay unit TR and automatic distant station selector DS. These units will now bediscussed in the order of their enumeration and with particular reference to FIG. 3 of the drawings.

Distributing box.--The distributing box DB which is adapted to be positioned in the midst of the mine field D consists of a suitably dimensioned annular casting having a base 230 and a cylindrical wall 231, formed with a circular flange 232. This flange is provided with a shore cable inlet 233 and nineteen mine cable outlets 234 for the passage of the nineteen conductors p1 to p18 inclusive, extending to the nineteen mines of the eld D. Bushings 236 which are disposed in the inlet and outlet openings 233 and 234 respectively are adapted to surround the conductors and prevent the ingress of water as will be readily understood without further discussion.

A cover 237 is adapted to` be bolted to ange 232 against the compressible gasket 238. A mounting or frame 239 is positioned within the casting and functions to support the distributing assembly. Frame 239 is encased by a cap member 240 having apertures in its top portion for the passage of the tips of fuses 241 (FIG. 13), and in this connection it might be noted that one of the fuses 241 is adapted to be -included in each of the mine circuits. Y

Locking relay una-Locking relay unit LR consists of a relay 242 including winding 243, armature 244 and arm 245 interlinked with and operated by the armature to move the switch set 246 to operated position. Switch set 246 includes a stack of contacts 1p to 7p inclusive of which contacts 2p and 5p are interconnected. In the normal or released position of the switch, contacts 11n-2p, lip-4p and 6p-7p are closed. Actuation of the switchset to its operated position opens the previously mentioned closed contacts and closes contacts 2p-4p and 5p-7p, for a purpose to hereinafter appear. The contacts of the switch set 246 are connected to the system as follows:

contact 1p to one end of conductor 252, contact 2p tol distributing terminal 253 to which the shore cable Y is also attached; contact 3p to ground 254, via conductor 255 and leakage resistance 256; contact 4p to resistance 248 via conductor 249'; contact 5p to ground 257 via conductor 258 and leakage resistance 259; contact 6p to one end of conductor 260 and contact 7p to the upper end of conductor 261. To include relay 242 in the system, the upper end of its winding 243 is connected to the distributing terminal 253 via conductor 248, resistance 248 and conductor 247. The remaining end of winding 243 is connected to ground 249 via conductor 250 and leakage resistance 251.

T imng relay unit.--The timing relay unit TR consists of a relay 262, including windings 262:1 and 262i), armature 263 and switch operating arm 264 interlinked with and operated by the armature to move switch set 265 to operated position. Switch set 265 includes a stack of contacts 1q-2q3q and 4g, of which contacts 2q and 4g are interconnected for simultaneous movement. These contacts are tied into the system as follows: Contact lq to ground 266 via conductor 267; contact 2q to one end of conductor 268'; contact Sq to conductor 252 via branch conductor 269; contact 4g to one end of conductor 279. To include the winding 262:1 of relay 262 in the system, one end of said winding 262@ is connected to the free end of conductor 260 and the opposite end to junction terminal 271 via conductor 272, resistance 273 and conductor 274. Winding 262b has its upper end connected to junction terminal 271 via conductor 275 and resistance 276. The opposite end of winding 262b is connected to ground 266.

Distant station Salacrou-The construction of the automatic selector DS in the distributing assembly C is substantially the same as that of the selector used in the casemate assembly B with exception of the wiper arrangement which in the case of the distant selector DS is modified so as to replace two of the four Wipers used in the casemate selector with a peripherally notched disk which is adapted to engage the lower row of contacts in the contact bank for a purpose to hereinafter appear. Reference being had to FIGS. 3,9, l and 14, of the drawings, the distant station selector DS comprises a motor magnet MN having a winding '279. The armature 279e of magnet MN is interlinked with and controls the movement of armature arm 280 and its depending stepping pawl 281. Energization of magnet MN moves the arm 280` to the left (FIG. andin so doing closes the normally open contacts-lr and 2r mounted upon the motor magnet. When magnet MN is deenergized, spring 282 returns arm 280 to its original or normal open position, as `shown in fFIGS. 3 and 10 of the drawings.l

The preceding structure is positioned upon a suitable base plate 283 adjustably associated wtih frame 284 of the contact bank CB, which is composed of three semicircular rows of contacts n n, b-b and c-c. For the purpose of this description the arcuate rows n n, b-b and c--c will be designated Upper Mine Level, Middle Mine Level and Fan Level respectively. The bank of contacts CB is adapted to be served by two wipers 285 and 286 and a disk 287, which rotates with the wipers and coacts with the contacts of `fan level c-c, as shown in FIG. 3 of the drawings.

Wipers 285 and 286 and disk 287 are mounted in insulated relation upon and keyed` to a shaft 288 suitably journalled in the parallel sides of base 283. Shaft 288 is provided with a ratchet 289 adapted lto be engaged by the pawl'28'1 for the purpose of causing a step-by-step rotaryimovement of the shaft and imparting a similar movement to the wipers .285, 286 and disk 287, keyed to the shaft, the movement of the two wipers as viewed from the'right being anti-clockwise and that of the disk as viewed from the opposite direction being clockwise, as indicated by the arrows FIG. 3.

Disk 287 serving fan level c-c is peripherally formed with diametrically opposed notches 290 which are adapted to underlie the contact-wiping-ends of the respective wipers 285 and 286 `and vto follow these wiping ends as they successively engage the contacts of their respective levels. Hence as the contact wiping ends of wipers 285 and 286 in the course of their step-by-step movement engage the contacts of levels a-a and b-b, one of the notches 290 will uncover the contact in the fan level c--c which is in electrical connection with thecontact in level a-a or b-b engaged by the wiping end of wipers 235 or 236 (FIG. 14). With this arrangement it will be seen that with exception of the contact uncovered by the notch the contacts of fan level c-c are always in engagementv l5 with the disk as it rotates. In other words one of the notches 290 will successively exclude one of the contacts of fan level c-c from the normal association of the contacts and the disk as the latter is rotated step-by-step with the two wipers.

The twelve contacts in mine level a-a include ten effective contacts designated m2, m4, m6 to m18 and h, the designations m2 to m18 representing the mine connected contacts and the character l1 the home contact. The fourteen contacts of mine level b--b include twelve effective contacts, ten being designated m1, m3, m5 to m19 and two t and h1, the contacts m1 to m19 representing the mine connected contacts, the contact t a testing contact and the contact h1 a home contact. The twentytive contacts of the fan level c-c include twenty active contacts designated s1 to S19 inclusive, representing the mine connected contacts and a home contact respectively. In this regard it is to be noted that the spacing of the contacts in levels a-a and b-b is such, when the wiping end of wiper 286 is in engagement with contact m1, the wiping end of wiper 285 is between the inactive contact and contact m2 of level a-a, land when the wiping end of wiper 236 is between the contacts m1 and m3 of level b-b the wiping end of wiper 285 is on contact m2 of level a-a and so on to the nineteen contacts.

The various contacts of the three levels a-a, b b and c-c are electrically interconnected as follows: contact m1, level b-b to contact s1 level c-c, via conductor nl; contact m2, level a--a to contact s2, level c-c via conductor n2; contact m3, level b-b to contact s3 level c-c via conductor n3; contact m4, level a-a to contact s4, level c-c via conductor n4; contact m5, level b-b to contact s5, level c-c via conductor nS; contact m6 and so on to the contact m19, level b-b which is connected to contact S19, level c-c via conductor 1119.

In level a-a the home contact h is connected to the free end of conductor 261 extending from contact 7p of locking relay LR (FIG. 3), In level b-b thel home contact h1 is connected to the free end of conductor 270 and the testing contact t to ground 292 via conductor 293, resistance 294 and conductor 295. In level c-c the home contact h2 is connected to ground 296 via conductor 297, as clearly shown in FIG. 3 of the drawings. The nineteen conductors n1 to n19 interconnecting the three levels a-a, b-b and c-c of the Contact bank are adapted to be connected via conductors o1 to 019 inclusive, with the lower ends of the nineteen mine fuses 241, the upper ends of these fuses being connected with the nineteen mines M1 to M19 via conductors p1 to p19.

In this connection, it is to be noted in passing, that it is one of the fuses 241 which is adapted to be blown by the clearing power, for the purpose of releasing the distant station selector so that it will step to the home position. Usually fuse 241 is blown with the mine, sometimes, however, this does not occur and in this event the fuse must be blown before the selector will release.

To electrically connect thedistant station selector DS with the system its two Wipers 285 and 286 which are interconnected by conductor 298 are connected to conductor 291 extending from conductor 250 (FIG. 3), while lthe disk 237 is connected to junction 271 via conductor 300.

Having outlined the various components of the distributing box assembly their construction and electrical connections, attention will now be directed to the mine field D.

DISTANT STATION- MINE FIELD Each of the nineteen mines forming the mine eld D includes a mine assembly E consisting of a circuit-closing relay unit CR, an impact-operated mine-arming mechanisrn IM adapted to coact with the relay unit CR, a resistance element inthe form of a neon tube and firing relay unit FR adapted to control suitable detonators. These components will now be considered in the order of their enumeration.

Circuit-closing relay unit CR is composed of a relay 301 including winding 302, armature 303 and armature arm 304, which is interlinked withand controlled by the movement of the armature 303.` The armature arm 304 is adapted to operate switch set 305 embodying a stack of contacts 1s, 2s and 3s, as shown in FIG. 3 of the drawings. To include switch set `305 in the instant system, contact 1s is connected to ground 306, via conductor 307; contact 2s to winding 302 at a point substantially midway of its length, via conductor 308; contact 3s to one side of the neon tube.309 via conductor 310. To electrically tie the winding 302 of the relay 301 into the instant system, the armature end of said winding is connected to mine tunnel 311 viaconductor i 312. Terminal 311 in each of the mine assemblies E, is

adapted to be connected to one of the nineteen conductors p1 to p19, extending from the distant station selector. In the illustrated embodiment terminal 311 is connected to conductor p19 which through fuse 241 and conductors 019-1119 is connected to contact m19, level b-b of the automatic selector. The remaining end of winding 302 is connected to the winding of the firing relay via conductor 312', resistance 313 and conductor 314. as shown in FIG. 3 of the drawings;

Coacting with switch set 305 is an impact mine arming mechanism comprising inclined surfaces 315 and 316 and a ball 317 upon which there normally rests a member 318 depending from contact 1s of switch set 305. This arrangement holds the contacts 1s-2s in spaced relation and maintains the normal unarmed condition of the mine, as shown in FIG. 3 of the drawings. When a mine has been struck, the impact rolls the ball along one of the inclined surfaces 315 or 316 and permits the lower end of member 318 to descend to the rear of the ball. This displacement of the ball and consequent drop movement of contact 1r, closes contacts 1s-2s and thus arms the mine. The armed status of the mine will continue until the circuit-closing relay 301 has been energized. When this occurs armature 303 will elevate armature arm 304 to engage contact 3s with depending contact element 304 of contact 1s. As the upward movement of the arm 304 continues it opens contacts 1s-2s and lifts member 318 from the path of the ball sufficiently to permit the latter to assume its original position. The mine is now in condition for the application of tiring power. Deenergization of relay 301, restores arm 304 to its original position and leaves the lower end of member 318 resting on top of the ball, with all contacts open. The mine impact mechanism and the contacts 1s, 2s and 3s are now in their normal position.

The resistance element in the form of a neon tube 309 is employed to provide a bypass to ground 306 for a current, the potential of which is suflicient to break down the resistance of the neon tube, as previously stated. One side of neon tube 309 is connected to contact 3s of switch set 305 via conductor 310 and the other side to ground 306 via conductors 319 and 307.

The tiring relay unit FR is composed of a relay 320 and a switch set 321. Relay 320 comprises winding 321', armature 322 and armature arm 323 which is connected with the armature 322 and is adaptedv to operate switch set 321 embodying a stack of contacts 1t to 4t inclusive, two of which 2t and 4t are interconnected for simultaneous movement. To include the switch set 321 in the system contact 1t is connected to the armature end of relay winding 302 Via conductor 325; contact2t to one of the binding posts 326 of detonator 327 via conductor 328, the remaining binding post 329 of detonator 327 is connected to one end of conductor 330; contact 3f is connected to binding post 331 of detonator 332 via conductor 333, which is also connected to the'free end of conductor 330. The remaining binding post 334 of detonator 332 is connected to conductor 328 via conductor 335. Contact 4t is connected to the lower end of winding 321 Via conductor 336.

To include the winding 321 of tiring relay FR in the system, they upper end of said winding is connected to contact 3s of switch set 305 via conductor 337 and the opposite end of said winding is connected as previously stated to winding302 via conductor 314, resistance 313 and conductor 312. When the tiring relay energizes, armature arm 323 moves switch set 321 to operated position and in so doing closes the. circuits including one of the detonators 327 and 332 to iire the mine.

The components of the several mine assemblies having been described, this discussion will be directed to the principal circuits of the instant system: Normal Operating Circuit; Stepping Circuit; Firing Circuit-Impact, Observation or Locking Circuit; Firing Circuit-Casemate Selected; Clearing Circuit; Selector synchronizing Circuits; Testing, Checking and Mine Signal Circuits.

CIRCUITS AND THEIR FUNCTION Normal operating circuit.-Assuming the casemate power unit (not shown) to be delivering the requisite power to the distributing terminals of the casemate assemblies A and B, the firing switch 43 to be closed, the dummy plug 126 to `be in group jack I (to connect the mine control assembly A to the supervisory assembly B), and that the components of the system are otherwise as shown on FIGS. l, 2 and 3 of the drawings; with this assumption, when operating switch 33 of mine control assembly A (FIG. l), has been closed, a circuit will be established from the llO volt direct current power distributing terminal 1 of the mine control assembly A, to the junction terminal 253 of distributing assembly C (FIG. 3), through diode'14, secondary winding 9 of transformer 7, winding 208 of m'otor magnet MM, a portion of winding 192 of synchronizing relay unit Q, cable Y extending between the casemate and distant stations) to junction 253.

This circuit may be traced as follows: (FIGS. l, 2, 3 and 4) power terminal 1, conductor 45, terminal 34a of operating switch 33, terminal 34C of said switch, conductor 17, anode and cathode 16 and 15 of diode 14, secondary winding 9 of transformer 7, conductors 53 and 57, contacts 1a, 2a of start switch 56, conductors 58 and 59, terminal 59a of terminal block 106, conductor 59b (FIG. 2, terminal 59e, conductors 131, 130 and 131', contacts 1li-2h (closed by insertion of dummy plug), conductors 133, 134, contacts 1i, 2i, check key K, conductors 143 and 213, winding 208 of motor magnet MM, conductors 215 and 214, contacts 211 and 212 of the motor magnet MM, conductor 184, contacts 2n-1n of the switch set 180 of impulse relay unit P, conductor 183, a portion of winding 192 of synchronizing relay unit Q, conductors and 157, contacts 7]'-Sj of milliammeter key L, conductor 137, contacts 4h-6h of group jack I, conductors 139 and 140, terminal 50c, conductor 5017, terminal 50a of terminal block 106 (FIG. l, conductor 50, contacts 2d-1d of control relay unit 78, conductors 83 and 83, winding 68 of pilot relay unit 67, conductor 84, ballast resistance Z and shore cable Y to junction 253. From the junction terminal 253 (FIG. 3), there are two paths which may be taken by the current to the ground 266. One of these paths is as follows: junction terminal 253, contacts 2p-1p of the switch set 246 of locking relay unit LR, conductor 252, winding 279 of motor magnet MM, conductor 268 contacts 2q-1q of switch set 265, of timing relay unit TR, conductor 267 to ground 266.

The other of the paths to ground 266 is as follows: junction terminal 253, conductor 247, resistance 248', conductor 248, winding 243 of locking relay unit LR, conductors 250 and 291, wiper 285 of distant station selector DS, home contact h, conductor 261, contacts 7p-6p of switch set 246 of locking relay unit LR, conductor 260, winding 262a of timing relay unit TR, conductor 272, resistance 273, conductor 274, junction 271, resist- 19 ance 276, conductor 275, winding 262b of timing relay unit TR to ground 266.

Closing operating switch 33 of the mine control assembly A, likewise completes a circuit from power terminal 1, through white light 28 to ground 36 as follows: power terminal 1, conductor 74, contacts 2c-1c, pilot relay unit 67, conductors 73 and 31, terminals 29 and 30 of the white signal lamp 28, conductor 32, contact 34b, operating switch 33, contact 34d, conductor 35 to ground 36. When power was applied to the terminal 1, its application established a circuit through guard relay unit 92 to ground 96 FIG. 1, as follows: power terminal 1, conductor 74, contacts 2c-1c of switch set 71 of pilot relay unit 67, conductors 73 and 31, resistance 95b, winding 93 of guard relay unit 92, conductor 96a to ground 96. This circuit energized guard relay unit 92 and' through its armature arm 95 moved switch set 95a to operated position, which opens contacts 1e-2e and disrupts the high potential ring power circuit from power terminal 4 to which 600 volts rectified alternating current has been applied. The system is now on the alert, that is to say, white light 28 is glowing at the casemate indicating that the distant station selector is on the home position; switch set 95a of guard relay unit 92 is in its operated position breaking the 600 Volt tiring circuit and switch set 265 of the timing relay unit TR FIG. 3, is likewise in operated position disrupting the circuit to motor magnet MN of the distant selector, as clearly shown in FIG. 5 of the drawings. Otherwise the components of the system are as shown n FIG. 1, 2 and 3 of the drawings.

Steppin-g dreier-With the system on the alert and ready for action, let it be assumed that an enemy vessel attempting to navigate the mine field D strikes one of its mines, for instance mine number 19. The impact of the vessel tilts the mine and causes ball 317 of the impact mechanism IM in mine assembly E (FIGS. 3 and 5), to descend one of the inclined surfaces 315 and 316. Displacement of ball 317 enables member 318 FIG. 5, to d-rop behind it, permitting contact 1s of switch set 305 of circuit closing relay unit CR to assume the dotted line position shown on FIG. 5 of the drawings, thus closing contacts 1s-2s of switch set 305 of the circuit-closing relay unit CR and establishing the ground 306. Since 110 volts of direct current are available at junction 253, FIGS. 3 and 5, when the ground 306 has been established, a circuit will be formed through winding 243 of locking relay unit LR, which is in its normal or unretracted position, wiper 285 of the distant station selector DS, winding 262e of timing relay unit TR, disk 287 of the distant station selector to ground 306 as follows: FIGS. 3 and 5, terminal 253, conductor 247, resistance 248', conductor 248, winding 243 of locking relay unit LR, conductor 250, wiper 285, home contact h, conductor 261, contacts 7g2-6p of switch set 246, conductor 260, winding 262a of timing relay unit TR, resistance 273, conductor 274, junction 271, conductor 300, disk 287, contact s19, engaged by the disk 287 FIG. 5, conductors 1119-019, fuse 241, conductor p19, a portion of winding 302 of the circuit-closing relay unit CR, conductor 308, contacts 2s-1s of switch set 3415, of circuit-closing relay unit CR, conductor 387 to ground 306.

Completion of the stepping circuit by mine impact causes the locking relay unit LR to function and to move its switch set 246 to operative position which opens contacts lip-2p, 3ra-4p, 6p-7p and closes contacts 2li-4p, Sli-7p. Opening contacts 11n-2p, .3p-4p, 6p-7p breaks the 110 volt supply circuit between punction 253 and conductor 252; cuts out the leakage path to ground 254 through resistance 256 and breaks the circuit through winding 262a of the timing relay unit TR which permits switch set 265 of said timing relay unit to return to its normal or unretracted position, as shown in FIG. 3 of the drawings. Closing contacts 2p-4p, Sp-'p provides leakage paths to ground 249 through resistance 251 and introduces the resistance 259 to ground 257 for a purpose hereinafter to be stated. With switch set 246 of locking relay unit LR in its retracted position and switch set 265 of timing relay unit TR in its normal or unretracted position the ground 306 established by mine impact, as previously stated, is momentarily cut out [contacts 6p-7p being open] and replaced by ground 257 in the circuit as follows: junction 253, conductor 247, resistance 248', conductor 248, winding 243 of locking relay unit LR, conductors 25tb-291, wiper 285, home position i1 of the distant station selector, conductor 261, contacts '7p-5p, resistance 259, ground 257. The formation of this circuit from junction 253 to ground 257 substitutes resistance 259 for resistance 273 and replaces the leakage path to ground 254 through resistance 256 with the leakage path to ground 249 via resistance 251. This change in the electrical characteristics of the circuit from junction 253 to ground 257 reduces the value of the current flow through the circuit below the holding requirements of locking relay unit LR which causes said locking relay unit to release its switch set 246. When the latter has returned to its normal position, contacts Zp-lp, 6p-7p will be closedto establish a ow of current from junction 253 to ground 266 through winding 279 of the motor magnet MN and contacts lag-2q of the switch set 265 of timing relay unit TR which energizes motor magnet MN, thereby causing the wiper 285 to leave its home position h for a purpose hereinafter to be stated. In this connection, it is to be noted that, when switch set 246 of the locking relay unit LR returns to its normal or unretracted position and before the wiper 285 of the distant station selector has left its home position h, ground 366 will have been re-established. As this circuit from junction 253 to ground 306 includes but one coil 26a of the timing relay unit TR, the switch set 265 of the latter (which is in its normal or unretracted position) will not be aected to disrupt the circuit through winding 279 of motor magnet MN. When motor magnet MN has been energized, its armature controlled arm 280 functions to close the motor magnet contacts 1r-'2r and to establish a circuit to ground 266 through winding 262b of the timing relay unit TR as follows: FIGS. 4 and 5, junction 253, contact 2p-1p of switch set 246, conductor 252, contacts lr-Zr, conductors 275 and 275, winding 262b of timing relay unit TR to ground 266.

This circuit causes the timing relay unit TR to function and to move its switch set 265 to operated position which opens contacts 1q-2q and breaks the circuit to ground 266 through the winding 279 of motor magnet MN. Motor magnet MN having been deenergized, its retractile spring FIGS. 9 and 10, retracts armature arm 280 and in so doing rotates the shaft 288 sufficiently to impart the starting step to the wipers 285 and 286 and disk 287 of the selector. As the wiper 285 leaves its home contact l1, the circuit from junction terminal 253 to ground 386 in mine assembly E, including winding 243 of locking relay unit LR, winding 262a of timing relay unit TR, and disk 287 is broken permitting return of the switch sets 246 and 265 to their normal positions. Meanwhile wiper 286 has engaged mine contact m1 and disk 287 stepping with the two wipers, has advanced its notch 296 one step to etfect engagement of Said disk and home contact h2 forming a circuit from junction 253 to ground 296, FIGS. 4 and 5, as follows: junction 253, conductor 247, resistance 248', winding 243 of locking relay unit LR, conductors 250 and 291, conductor 298, mine contact m1, conductor nl, mine Contact s1, disk 287, home contact h2, conductor 297 to ground 296. Throughout the period that the circuit just described from junction 253 to ground 266 through disk 287 remains effective, switch set 246 of locking relay unit LR retains its normal or unretracted position while switch set 265 is alternately retracted and reelased to cause the operation of the stepping magnet MN. In this connection it is to be understood that the complete circuit from power terminal 1 21 to junction terminal 253 remains the same as originally traced, as shown in FIG. 4 of the drawings.

When the preceding circuit from junction 253 to ground 296 via disk 287 has been established, a steady ground will be provided for the stepping operation of the selector in the supervisory assembly B at the casemate or shore station, so that the latter will function in proper coordinative sequence with respect to the distant station selector DS which is stepping by virtue ofthe circuit established from junction 253,` contacts Zp-lp of switch set 246 of locking relay LR, conductor 252, motor magnet winding 279, conductor 268', contacts 2q-1q, switch Set 265 of timing relayunit TR, conductor 267 to ground 266. This circuit through the winding 279 of motor magnet MN moves the armature of the motor magnet tothe left FIG. 9, and positions the end of stepping pawl 281 so that it will engage one of the teeth of ratchet 289. As the arm 280 of the motor magnet moves to the left, itl

closes contacts 1r-2r and in so doing completes a circuit from junction 253 to ground 266, FIGS. 4 and 5 as` follows: junction 253, contacts 2p-1p, switch set 246 of locking relay Yunit LR, conductor 252, contacts 1r-2r now closed) conductors 275' and 275, winding 262b of. timing relay unit TR to ground 266. This circuit through the winding 262b of the timing relay unit TR moves its switch set 265 to operative position breaking the current through winding 279 of the motor magnet MN. When the circuit of motor magnet MN has been broken the impeller spring 28'2, becomes effective to restore the armature arm to its initial position. The return movement of armature arm 280 causes stepping pawl 281 engaging one of the teeth in ratchet 289, to impart the requisite stepping movement to the wiper arms 285 and 286 and disk 287.

As the wipers 285 and 286 of the distant station selector alternately enage their respective mine contacts, the circuit from junction terminal 253 to ground 296 will be formed repeatedly to produce the required ilow of current from terminal 253 to ground 266, through the motor magnet winding 279, along the alternate paths hereinbefore described, causing the distant station selector to continue its stepping movement until the mine contact m19 which is in circuit with ground 306 has been reached by the wiper arm 286, whereupon said arm will be stopped on the grounded mine contact, as will be hereinafter described. Assuming that none of the mine contacts are grounded, when wipers 285 and 286 reach home position h and h1, notch 290 in disk 287 will register with home position h2, thereby disconnecting the disk and ground 296 and disrupting the circuit from junction terminal 253 to ground 296 to stop the distant selector on the home position.

inasmuch as the casemate selector CS is controlled by the distant selector, said casemate selector will likewise stop on the home position. If one of the mine contacts of the distant selector has been grounded the wipers 285 and 286 will continue to step to and lock on, the grounded mine contact until said ground has been eliminated, as will hereinafter appear. The operation of the casemate and distant selectors produces a pulsa-ting current through the system which momentarily operates the switch sets of the various relay units. To prevent this movement of the switch sets completing the high potential firing power circuit to the distant selector, the guard relay unit 92 (FIG. l) has the armature of its relay counterweighted as at 94a so that this unit will not respond to the action of the pilot relay unit until the latter has moved its switch set 71 to operated position and has permanently retained the set in this position.

1 The automatic selector at the casemate is adapted to step in coordinated sequence with the stepping movement of the distant station selector DSl and to effect this operation several paths are made available to the current as it flowsfrom junction 143e (FIGS. 2 and 4), to conductor 155, which as previously indicated is normally in circuit with the junction terminal 253, at the distant station. One of the paths available to the current flow is as follows: junction 143e, conductor 213, winding 208 of motor magnet MM, conductors 215 and 214, motor magnet contacts 211 and 212, conductor 184, contacts 2n-1 of switch set 180 of impulsing relay unit P, conductor 183, a portion of winding 192 of synchronizing relayunit Q, conductor to junction 253 (FIG. 3). Another path simultaneously'available to the ow of the current fromjunction 143e is as follows: junction 143e, winding 208, conductor 188, contacts 5ft-611 of switch set 180 of impulsing relay unit P, winding d of the impulse relay unit P, conductor 189, winding 192 of synchronizing relay unit Q to conductor 155 and thence to junction terminal 253 (FIG. 4). t

The flow of current through winding 208 of the motor magnet MM along the paths defined, elects its energization and retracts armature arm 210. At the same time the current owing through winding d of impulse relay unit P energizes and moves its switch set to operated position. The operation of switch set 180 breaks the two paths through winding 208 of the magnet, one of which includes a part of winding 192 of synchronizing relay Q, the other of which includes the winding d of impulsing relay P and the entire winding 192 of synchronizing relay Q. In this connection it is to be noted that, as the operation of switch set 180 of impulsing relay P disrupts the circuit through a part of winding 192 of the synchronizing relay Q, a substitute circuit is provided by the engagement of contacts 411 and 6n of impulsing relay P, which circuit extends from conductor 143 through conductor 187, contacts 411 and 6n, winding d, impulsing relay P, and winding 192 of synchronizing relay Q to conductor 155 (see FIG. 4), thus inserting in the circuit the windings d and 192 of impulsing and synchronizing relays P and Q, respectively, as winding 208 of the motor magnet MM is cut out. Armature arm 210 of the motor magnet as it moves to i-ts retracted position against the action of the retractile spring (not shown), breaks the circuit through the winding 208 by separating the contacts 211 and 212. When thus deenergized, the retractile spring (which is adapted to be connected to the armature arm 210), restores said arm to its original position, whereupon the circuits through the winding 208 from junction 143e to the conductor 155 are reformed. Movement of armature arm 210 to normal position by the spring (not shown) causes the stepping pawl (not shown) adapted to be carried by arm 210, to rotate shaft 207' of the contact bank sufficiently to move the wipers 204 to 207 ahead one step, as will be understood without further discussion. The sequence of operation of the casemate selector CS and the distant station selector DS, is arranged so that when the casemate selector CS has just stepped ahead the distant station selector DS has just retracted on the previous mine contact. As the current flows from junction 143e through winding 208 of the motor magnet MM to conductor 155,- it passes through winding 192 of synchronizing relay unit Q and energizes said relay to move its switch set 195 to operative position. When in this position the contacts 10-20 of switch set 195 are open and the circuit to the ground 199 which also includes winding 208, is broken. Unless broken the circuit to ground 199 would step the selector to its home position, as will hereinafterfappear.

Assuming that the casemate and distant station selectors have left their home positions and are stepping in the required coordinated sequence andv that wiper 286 of the distant station selector is about to contact mine contact m19, which as previously stated, is connected to the ground 306 by the impact of a vessel with the mine; when wiper 286 of -the distant station selector engages mine contact m19 an electrical path will be established Vfrom junction terminal 253 (FIGS. 3 and 5), through the winding 243 of locking relay unit LR, wiper 286, contact m19, 

